make a directory in your ut2003 dir called dbbeta, extract all the 1.9 stuff into this dir (maps/.u/.gfx etc)
copy your deathball.ini file, and rename it dbbeta.ini.
Add the following lines to your dbbeta.ini, BEFORE the other paths=system ones under the [Core.System] section :
Paths=../dbbeta/*.u
Paths=../dbbeta/*.ut2
Paths=../dbbeta/*.utx
Paths=../dbbeta/*.uax
Paths=../dbbeta/*.umx
Paths=../dbbeta/*.usx
Paths=../dbbeta/*.ukx
Paths=../dbbeta/*.uvx
it should look like this, or close to this after:
[Core.System]
PurgeCacheDays=30
SavePath=../Save
CachePath=../Cache
CacheExt=.uxx
Paths=../dbbeta/*.u
Paths=../dbbeta/*.ut2
Paths=../dbbeta/*.utx
Paths=../dbbeta/*.uax
Paths=../dbbeta/*.umx
Paths=../dbbeta/*.usx
Paths=../dbbeta/*.ukx
Paths=../dbbeta/*.uvx
Paths=../System/*.u
Paths=../Maps/*.ut2
Paths=../Textures/*.utx
make a shortcut to your ut2003.exe with the following params
click on the shortcut to play 1.9, use your normal exe for 1.8